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MS: Massenspektrometrie

MS 8: Methodische Entwicklungen der MS

MS 8.2: Talk

Thursday, March 16, 2006, 14:30–14:45, H1

Mass spectrometric analysis of biomolecules laser desorbed from liquid micro droplets. — •N. Morgner, H.-D. Barth, and B. Brutschy — Inst f Phys and Theo Chemistry, University Frankfurt/M, Marie-Curiestr. 11, 60439 Frankfurt

We recently introduced a new MS method, (LILBID : laser induced liquid beam/bead ion desorption)[1], where solvated biomolecules are desorbed/ablated from a liquid droplet (φ = 50  µ m) into vacuum by resonant excitation of vibrations in the solvent by a pulsed IR laser. LILBID is a highly sensitive and soft detection method and tolerant to salt, detergents and various buffers, which may be one of the key advantages over the well established ESI-MS. It allows to detect preformed specific non covalently bonded biocomplexes in solution, such as ligands binding specifically to DNA-duplexes. It is applicable to a wide range of biomolecules from peptides and aminoacids over RNA and DNA to large membrane proteins such as cytochrome-c-oxydase. We will present results on the temperature dependent formation of DNA duplexes of different length/different melting points. To better characterize the mechanism of ion formation in LILBID, we report the dependence of ion-yield and charge state distribution on ion-strength, dielectric constant, pH-value and various buffers of the solution and the intensity and wavelength of the ablation IR laser. First results of the static binding behaviour of caged versus uncaged aptamers to thrombin was investigated for preparation of a kinetic study of quadruplex formation of the aptamer.

[1] N. Morgner, H.-D. Barth, B. Brutschy; accepted for publication in Australian Journal of Chemistry, Vol 59, No 1 (2006)